354 Scientific Proceedings, Royal Dublin Society. 



schist being highly impregnated with iron (marcasite), -while in 

 depth or nearer the centre it is not so. In depth the rock seems to 

 become less and less pyritous ; so that, if well selected, clean bright 

 stones may be procured. There are also in these granites black 

 or greyish, more or less pyritous, micaceous eyes, the majority of 

 which, especially if they have a pyritous margin, weather into a 

 rusty spot on the face of an otherwise bright clean stone. 



From the structures in which this stone has been used we learn 

 that the badly selected stone will become rusty, and remain so, 

 while the better class, after a time, lose the rust speckles, and 

 become clean and bright. It would appear, therefore, that the faces 

 of the good stones, if treated with acid {hydrochloric, or that acid 

 mixed with nitric), might be artificially weathered, thereby getting 

 rid of all the surface iron prior to the stones being used. The iron 

 in the " eyes," except where it occurs as a vein, might be similarly 

 got rid of. 



In the new railway station, Westland-row, Dublin, the granite 

 for rubble was brought from Kingstown, Sandycove, and Dalkey, 

 most of it being procured while doubling the line from Kingstown 

 to Killiney. The granite for cut-stone purposes came from Dalkey, 

 Kingstown, and Aughrim, Co. Wicklow. In the Loop Line (City 

 of Dublin Junction Railway), the granite for cut-stone purposes 

 has been principally procured from Aughrim, Co. Wicklow, but 

 some is Co. Dublin granite. (T. B. Grierson.) 



